(a) Field of the Invention
The present invention relates to a thin film transistor array panel for a display and a manufacturing method thereof.
(b) Description of the Related Art
A liquid crystal display (“LCD”) is one of the most widely used flat panel displays. The LCD, which includes two panels with respective electrodes and a liquid crystal layer with dielectric anisotropy disposed therebetween, displays desired images by applying an electric field to the liquid crystal layer to control the amount of light passing through the panels.
The most frequently used type of LCD are those having a plurality of electrodes formed on two panels and a plurality of thin film transistors (“TFTs”) for switching voltages applied to the electrodes. One of the two panels has a plurality of signal lines, such as gate lines and data lines, a plurality of pixel electrodes and the TFTs controlling image signals transmitted to the pixel electrodes. The other panel has a common electrode opposite to the pixel electrodes and an array of color filters of red R, green G and blue B.
The respective panels are normally manufactured by a photo etching process using masks. The panel with the TFTs is generally manufactured by using five or six masks and the other panel with the color filters is manufactured by using three or four masks.
In this manufacturing method of the LCD, it is preferable to decrease the number of masks so as to reduce production cost, and to simplify a manufacturing process.
In addition, it is a main task to secure high aperture ratio of the panels so as to increase the brightness of the LCD. For this, a method, which forms the color filters on the same panel together with the TFTs to minimize a process margin between the two panels for increasing the aperture ratio, has been provided, and an organic insulating layer having excellent planarization characteristics is formed on the color filters so as to improve the profile of other layers formed thereafter.
However, in this manufacturing method of the LCD, contact holes for connecting drain electrodes of the TFTs to the pixel electrodes are formed in the color filters and the organic insulating layer. Since the color filters and the organic insulating layer are all organic layers and are too thick, it is hard to obtain good profiles of contact holes during an etching process. An addition photo etching process may solve the problem, but this causes complexity.